Jessica Simpson has spoken for the first time about her split with hubby Nick Lachey. The Dukes of Hazzard stunner has revealed that she was miserable towards the end of their relationship. And she confessed she had no idea why they started to drift apart. Last night she said: "You have to realise that if you're not happy, you can't make anybody else happy. "I don't know what happened to me ... it's so strange. "I'm just proud of allowing myself to think and act and be." She added: "I feel free. I feel like I can do anything and there's nobody to answer to but myself." Jessica, 25, reveals she still talks to Nick, 32, every few days. She left the former boy-band star in December after three years of marriage. She tells the forthcoming issue of American fashion magazine W that they are "absolutely" still friends, and she hopes speaking out will help to mend her broken heart. She added: "It's like girl time, a healing within, in a lot of ways." Friends say Jessica is determined to shed her public images as a dizzy blonde. A pal told US magazine In Touch Weekly: "She is sick of being the ditzy blonde. "She wants to show the world that she has a brain." Jessica also tells W magazine that she is set to publish a volume of poetry, which she has been writing since she was 11. She adds: "It's a piece of my heart I want to share with my fans."